# -*- coding: utf-8 -*-
"""
Created on Tue Jul  9 18:01:50 2019

@author: jingzl
"""

# 基本统计值计算

def getNum():
    nums = []
    iNumStr = input("请输入数字（回车退出）：")
    while iNumStr != '' :
        nums.append( eval(iNumStr) )
        iNumStr = input("请输入数字（回车退出）：")
    return nums

def mean( numbers ):
    s = 0.0
    for num in numbers:
        s = s + num
    return s / len(numbers)

def dev( numbers, mean ):
    sdev = 0.0
    for num in numbers:
        sdev = sdev + ( num - mean ) ** 2
    return pow( sdev / ( len(numbers) - 1 ), 0.5 )

def median( numbers ):
    sorted( numbers )
    size = len(numbers)
    if size % 2 == 0:
        med = ( numbers[size//2-1] + numbers[size//2])/2
    else:
        med = numbers[size//2]
    return med

n = getNum()
m = mean(n)
print("平均值：{},方差：{:2},中位数：{}.".format(m,dev(n,m), median(n)))








